The present invention relates to a tire vulcanizing press and more particularly to an improved hydraulic tire vulcanizing press of the type including an upper frame, a lower frame and both side frames, wherein a die comprising an upper die half and a lower die half is tightly closed by means of a raising and lowering table fixedly secured onto the upper die half, said raising and lowering table being adapted to be raised up or lowered with the aid of a hydraulic press.
A hitherto known hydraulic tire vulcanizing press is generally constructed so that a raising and lowering table has a working stroke of about 1,000 mm in case of tires for a passenger car or about 2,000 mm in case of tires for a truck or like vehicle so as to allow a green tire to be vulcanized to be loaded on the lower die half and therefore a hydraulic cylinder for tightly closing both the die halves is designed to have a correspondingly long working stroke. Accordingly, when there occurs pressure reduction due to leakage of a hydraulic oil from packings on hydraulic line in the vulcanizing press during tire vulcanizing, there is fear of causing an amount of die opening between both the die halves to exceed the specified limitative value, resulting in an occurance of leakage of vulcanizing medium (steam, high pressure and temperature water, high pressure and temperature gas or the like) from the interior of the die. To take remedial activity against malfunctions as described above there have been already made various proposals. One of them is to employ expensive components such as a breach lock ring or like means and another one is to mount a hydraulic control device or the like adapted to be actuated by means of a pressure switch. However, it has been found that any one of these proposals fails to function properly as means for minimizing an amount of die opening between both the die halves.